This application addresses broad Challenge Area (04): Clinical Research and specific Challenge Topic 04-HD- 102*: Development of Pediatric Medical Devices. Radiation dose in pediatric cardiac interventions is a serious concern because of the far greater likelihood for children to develop cancer when exposed to radiation than adults. It is preferable to use imaging modalities that do not rely on ionizing radiation (e.g. MRI, ultrasound), but currently these modalities cannot provide the real time imaging and spatial resolution performance necessary for cardiac interventions. Therefore, we propose to develop an interventional cardiac fluoroscope that will significantly reduce the radiation dose to children. We, Triple Ring Technologies and the University of Wisconsin, have developed an adult-oriented cardiac angiography system for the catheterization laboratory, scheduled for release in fall 2009. The system employs a novel imaging geometry with an extended, scanning-beam X-ray source based on a transmission target, and a pixelated photon counting detector. The final image is composed of up to 10,000 detector images that are reconstructed in real time. This scanning-beam digital X-ray (SBDX) system was designed and proven to reduce radiation exposure in adult patients as much as 10-fold. These savings are expected to be smaller in children due to their smaller size and procedural requirements. However, we believe that the unique design of the SBDX system will allow the implementation of additional dose saving strategies benefiting pediatric patients that are not possible in conventional systems. These are: (Specific Aim 1) Use of a novel target in combination with beam filtration that has an enhanced spectral composition to improve image contrast for iodine;(Specific Aim 2) Energy-resolved detection to further enhance image contrast;and (Specific Aim 3) Electronic spatial beam shaping including ROI filtration, collimation, and equalization filtration that does not rely on mechanical filters or shutters. We will validate our approach in a comparative study of anthropomorphic pediatric phantoms with a conventional system and the proposed pediatric SBDX system (Specific Aim 4). We believe these strategies will reduce radiation dose in children by 75% as compared to conventional systems using pediatric settings. Radiation dose in pediatric cardiac interventions is a serious concern because children who receive radiation in the first decade of life have a several fold higher risk of developing cancer than the average population. It is preferable to use imaging technologies that do not rely on ionizing radiation (e.g. MRI, ultrasound), but currently these technologies cannot provide the real-time imaging and spatial resolution performance necessary for cardiac interventions. Therefore, we aim to develop and build a prototype fluoroscope for pediatric cardiac interventions that will reduce the radiation dose to children by 75% as compared to conventional systems using pediatric settings.